Sensor, thin film transistor array panel, and display panel including the sensor

ABSTRACT

A sensor is provided, which includes a substrate, an insulating layer formed on the substrate, a semiconductor formed on the insulating layer, an ohmic contact formed on the semiconductor, a sensor input electrode and a sensor output electrode formed on the ohmic contact, and a passivation layer formed on the sensor input electrode and the sensor output electrode. A sensor control electrode may also be formed between the substrate and the insulating layer. A thin film transistor array panel including the sensor and a liquid crystal display panel including the sensor are further provided.

This application claims priority to Korean Patent Application No.10-2005-0004879, filed on Jan. 19, 2005 and all the benefits accruingtherefrom under 35 U.S.C. §119, and the contents of which in itsentirety are herein incorporated by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a sensor, a thin film transistor arraypanel including the sensor, and a display panel including the sensor.More particularly, the present invention relates to an improvedtemperature sensor, a thin film transistor array panel including thetemperature sensor, and a display panel including the temperaturesensor.

(b) Description of the Related Art

Display devices used for monitors of computers and television setsgenerally include self-emitting display devices such as organic lightemitting displays (“OLEDs”), vacuum fluorescent displays (“VFDs”), fieldemission displays (“FEDs”), and plasma panel displays (“PDPs”), andnon-emitting display devices such as liquid crystal displays (“LCDs”)requiring an external light source.

An LCD includes two panels provided with field-generating electrodes anda liquid crystal (“LC”) layer having dielectric anisotropy interposedtherebetween. The field-generating electrodes supplied with electricvoltages generate an electric field across the LC layer, and the lighttransmittance of the LC layer varies depending on the strength of theapplied field, which can be controlled by the applied voltages.Accordingly, desired images are displayed by adjusting the appliedvoltages.

The light for an LCD may be provided by lamps equipped at the LCD or mayinstead be natural light.

Since optical characteristics of the liquid crystal within the LC layerare changed based on temperature, a temperature variation of the LCD hasto be considered for improving reliability thereof.

That is, since the optical characteristics such as refractive index,dielectric constant, coefficient of elasticity, and viscosity of theliquid crystal are in inverse proportion to thermalization energy ofliquid crystal molecules within the LC layer, values of the opticalcharacteristics decrease as the temperature of the liquid crystalbecomes higher. Thus, to optimize a state of the liquid crystal for gooddriving of the LCD, the temperature variation of the LCD due to internalheating and temperature within the ambient environment has to bedetected.

A temperature sensor is disposed on a printed circuit board (“PCB”)mounted with a plurality of driving circuits to detect a temperaturevariation of the LCD. However, the PCB is generally disposed on a rearside of the LCD, on which the lamps and electric elements generatingheat are disposed, instead of a front side thereof, on which the LClayer is installed, adjacent to the outside. Thus, the temperaturesensor detects a temperature at the rear side which has a largetemperature deviation caused by the heat. As a result, since thedetected temperature by the temperature sensor has a large differencewith respect to a temperature of the LC layer, temperature compensationof the LCD based on the temperature of the LC layer is not preciselyachieved. In addition, since the temperature sensor is separatelyinstalled on the PCB, design redundancy of the LCD and manufacturingcost are increased.

BRIEF SUMMARY OF THE INVENTION

The present invention solves the problems of conventional techniques.

In an exemplary embodiment of the present invention, a sensor isprovided, which includes a sensor control electrode formed on asubstrate, an insulating layer formed on the sensor control electrode, asemiconductor formed on the insulating layer, an ohmic contact formed onthe semiconductor, a sensor input electrode and a sensor outputelectrode formed on the ohmic contact, and a passivation layer formed onthe sensor input electrode and the sensor output electrode.

The insulating layer may be further formed on portions of the substratenot covered by the sensor control electrode. The passivation layer maybe further formed on portions of the semiconductor not covered by theohmic contact, sensor input electrode, or sensor output electrode, andon portions of the insulating layer not covered by the semiconductor,ohmic contact, sensor input electrode, and sensor output electrode.

The sensor input electrode may include a plurality of first branchesspaced by a predetermined distance and formed as a comb, and the sensoroutput electrode includes a plurality of second branches spaced by apredetermined distance and formed as a comb, wherein the first branchesare engaged with the second branches through the semiconductor,respectively. The first branches may be alternately arranged withrespect to the second branches.

The sensor may include a first signal line connected to the sensorcontrol electrode, a second signal line connected to the sensor inputelectrode, and a third signal line connected to the sensor outputelectrode. The passivation layer may be further formed on the sensorcontrol electrode and may include a first contact hole exposing aportion of the first signal line, a second contact hole exposing aportion of the second signal line, and a third contact hole exposing aportion of the third signal line.

The sensor may further include contact assistants connecting the firstsignal line and second signal line through the first and second contactholes, respectively, and the contact assistants may be made of indiumtin oxide (“ITO”) or indium zinc oxide (“IZO”). The second signal linemay be connected to a voltage through the second contact hole, and thevoltage may be a ground voltage. The third signal line may output asensing signal, and the semiconductor may be made of amorphous silicon.The sensor may thus be a diode type of temperature sensor.

In a further embodiment of the present invention, a sensor is provided,which includes an insulating layer formed on a substrate, asemiconductor formed on the insulating layer, an ohmic contact formed onthe semiconductor, a sensor input electrode and a sensor outputelectrode formed on the ohmic contact, and a passivation layer formed onthe sensor input electrode and the sensor output electrode.

The insulating layer may be further formed on portions of the substratenot covered by the sensor control electrode. The passivation layer maybe further formed on portions of the semiconductor not covered by theohmic contact, sensor input electrode, or sensor output electrode, andon portions of the insulating layer not covered by the semiconductor,ohmic contact, sensor input electrode, and sensor output electrode.

The sensor input electrode may include a plurality of first branchesspaced by a predetermined distance and formed as a comb and the sensoroutput electrode may include a plurality of second branches spaced by apredetermined distance and formed as a comb, wherein the first branchesare engaged with the second branches through the semiconductor,respectively. The first branches may be alternately arranged withrespect to the second branches.

The sensor may further include a sensor input line connected to thesensor input electrode and a sensor output line connected to the sensoroutput electrode, and the passivation layer may include a first contacthole exposing a portion of the sensor input line and a second contacthole exposing a portion of the sensor output line.

The sensor input line may be connected to a voltage through the firstcontact hole, and the voltage may be a ground. The sensor output linemay output a sensing signal. The sensor may thus be a resistor type oftemperature sensor.

In a still further embodiment of the present invention, a thin filmtransistor array panel is provided, which includes a gate line and asensor control electrode formed on a substrate, an insulating layerformed on the gate line and the sensor control electrode, and asemiconductor formed on the insulating layer, an ohmic contact formed onthe semiconductor. A data line, a drain electrode, a sensor inputelectrode, and a sensor output electrode are formed on the ohmiccontact, and a passivation layer is formed on the data line, the drainelectrode, the sensor input electrode, and the sensor output electrode.

The sensor input electrode may include a plurality of first branchesspaced by a predetermined distance and formed as a comb and the sensoroutput electrode may include a plurality of second branches spaced by apredetermined distance and formed as a comb, wherein the first branchesare engaged with the second branches through the semiconductor,respectively.

The panel may further include a sensor control line connected to thesensor control electrode, a sensor input line connected to the sensorinput electrode, and a sensor output line connected to the sensor outputelectrode. The passivation layer may further be formed on the sensorcontrol electrode and may include a first contact hole exposing aportion of the sensor control line, a second contact hole exposing aportion of the sensor input line, and a third contact hole exposing aportion of the sensor output line, and it may further include a fourthcontact hole exposing a portion of the drain electrode.

The panel may further include a pixel electrode connected to the drainelectrode through the fourth contact hole, and contact assistantsconnected to the sensor control line, the sensor input line, and thesensor output line through the first, second, and third contact holes,respectively. The contact assistants may be formed on the same layer asthe pixel electrode.

The sensor control electrode, the sensor input electrode, and the sensoroutput electrode may be formed on a border of the panel. The sensorcontrol electrode, sensor input electrode, and sensor output electrodeform part of a diode type of temperature sensor.

In a still further embodiment of the present invention, a thin filmtransistor array panel is provided, which includes a gate line formed ona substrate, an insulating layer formed on the gate line, asemiconductor formed on the insulating layer, an ohmic contact formed onthe semiconductor. A data line, a drain electrode, a sensor inputelectrode, and a sensor output electrode are formed on the ohmiccontact, and a passivation layer is formed on the data line, the drainelectrode, the sensor input electrode, and the sensor output electrode.

The sensor input electrode includes a plurality of first branches spacedby a predetermined distance and formed as a comb, and the sensor outputelectrode includes a plurality of second branches spaced by apredetermined distance and formed as a comb, wherein the first branchesare engaged with the second branches through the semiconductor,respectively.

The panel may further include a sensor input line connected to thesensor input electrode and a sensor output line connected to the sensoroutput electrode, wherein the passivation layer comprises a firstcontact hole exposing a portion of the sensor input line and a secondcontact hole exposing a portion of the sensor output line. Thepassivation layer may further include a third contact hole exposing aportion of the drain electrode.

The panel may further include a pixel electrode connected to the drainelectrode through the third contact hole. The panel may further includecontact assistants connected to the sensor input line and the sensoroutput line through the first and second contact holes, respectively,and the contact assistants may be formed on the same layer as the pixelelectrode.

The sensor input electrode and the sensor output electrode may be formedon a border of the panel. The sensor input electrode and the sensoroutput electrode form part of a resistor type of temperature sensor.

In yet a further embodiment of the present invention, a liquid crystaldisplay panel includes a first panel, a second panel, a liquid crystallayer disposed between the first panel and the second panel, and atemperature sensor formed on a first surface of the first panel, thefirst surface of the first panel facing the liquid crystal layer.

The first panel may be a thin film transistor array panel. Thetemperature sensor may be formed on a non-display region of the firstpanel. A plurality of temperature sensors may be formed on the firstsurface of the first panel.

The first panel may include at least one data line, and the temperaturesensor may include a sensor input electrode and a sensor outputelectrode formed within a same layer of the first panel as the dataline. The first panel may include a substrate and at least one gate lineformed on the substrate, and the temperature sensor may include a sensorcontrol electrode formed on the substrate within a same layer of thefirst panel as the gate line.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more apparent by describing preferredembodiments thereof in detail with reference to the accompanyingdrawings, in which:

FIG. 1 is a block diagram of an exemplary embodiment of an LCD accordingto the present invention;

FIG. 2 is an equivalent circuit diagram of an exemplary embodiment of apixel of an LCD according to the present invention;

FIG. 3 is a plan view of an exemplary embodiment of an LCD according tothe present invention;

FIG. 4 is a layout view of an exemplary embodiment of an LCD accordingto the present invention;

FIG. 5A is a sectional view of the LCD shown in FIG. 4 taken along lineVA-VA′;

FIG. 5B is a sectional view of the LCD shown in FIG. 4 taken along lineVB-VB′;

FIG. 6A is an equivalent circuit diagram of one exemplary embodiment ofa diode type of temperature sensor that may be used in an embodiment ofthe present invention;

FIG. 6B is a graph showing a characteristic of an output voltage withrespect to a temperature variation of the diode type of temperaturesensor shown in FIG. 6A;

FIG. 7A is an equivalent circuit diagram of one exemplary embodiment ofa resistor type of temperature sensor that may be used in an embodimentof the present invention;

FIG. 7B is a graph showing a characteristic of an output voltage withrespect to a temperature variation of the resistor type of temperatureshown in FIG. 7A;

FIG. 8A is a layout view of another exemplary embodiment of a resistortype of temperature sensor according to the present invention;

FIG. 8B is sectional view of the resistor type of temperature sensorshown in FIG. 8A taken along line VIIIB-VIIIB′;

FIG. 9 is a graph showing an output voltage with respect to atemperature variation in an exemplary embodiment of a diode type oftemperature sensor according to the present invention; and

FIG. 10 is a graph showing an output voltage with respect to atemperature variation in an exemplary embodiment of a resistor type oftemperature sensor according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein.

In the drawings, the thickness of layers and regions are exaggerated forclarity. Like numerals refer to like elements throughout. It will beunderstood that when an element such as a layer, film, region,substrate, or panel is referred to as being “on” another element, it canbe directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present.

Sensors and thin film transistor (“TFT”) array panels having a sensoraccording to embodiments of the present invention will be described withreference to the drawings.

FIG. 1 is a block diagram of an exemplary embodiment of an LCD accordingto the present invention, FIG. 2 is an equivalent circuit diagram of anexemplary embodiment of a pixel of an LCD according to the presentinvention, and FIG. 3 is a plan view of an exemplary embodiment of anLCD according to the present invention.

Referring to FIG. 1, an LCD includes an LC panel assembly 300, a gatedriver 400 and a data driver 500 that are connected to the LC panelassembly, a gray voltage generator 800 connected to the data driver 500,a temperature sensing unit 50, and a signal controller 600 controllingthe above-described elements.

With additional reference to the circuital views of FIGS. 1 and 2, theLC panel assembly 300 includes a lower panel 100 as a thin filmtransistor (“TFT”) panel, an upper panel 200 as a color filter panel,where the panels 100 and 200 face each other, and a liquid crystal layer3 interposed therebetween. The LC panel assembly 300 further includes aplurality of display signal lines G1-Gn and D1-Dm and a plurality ofpixels connected thereto and arranged substantially in a matrix.

The display signal lines G1-Gn and D1-Dm are provided on the lower panel100, and include a plurality of gate lines G1-Gn transmitting gatesignals (also referred to as “scanning signals”) and a plurality of datalines D1-Dm transmitting data signals. The gate lines G1-Gn extendsubstantially in a row direction and are substantially parallel to eachother, while the data lines D1-Dm extend substantially in a columndirection and are substantially parallel to each other.

Each pixel includes a switching element Q connected to the displaysignal lines G1-Gn and D1-Dm, and an LC capacitor C_(LC) and a storagecapacitor C_(ST) that are connected to the switching element Q. In analternative embodiment, the storage capacitor C_(ST) may be omitted ifit is unnecessary.

The switching element Q, such as a TFT, is provided on the lower panel100 and has three terminals including a control terminal connected toone of the gate lines G1-Gn, an input terminal connected to one of thedata lines D1-Dm, and an output terminal connected to the LC capacitorC_(LC) and the storage capacitor C_(ST).

The LC capacitor C_(LC) includes a pixel electrode 190, provided on thelower panel 100, and a common electrode 270, provided on the upper panel200, as two terminals. The LC layer 3, interposed between the twoelectrodes 190 and 270, functions as a dielectric of the LC capacitorC_(LC). The pixel electrode 190 is connected to the switching element Q,and the common electrode 270 covers an entire surface, or substantiallythe entire surface, of the upper panel 200 and is supplied with a commonvoltage Vcom. Alternatively, the pixel electrode 190 and the commonelectrode 270 may both be provided on the lower panel 100, and at leastone of the pixel electrode 190 and the common electrode 270 may haveshapes of bars or stripes.

The storage capacitor C_(ST) is an auxiliary capacitor for the LCcapacitor C_(LC). The storage capacitor C_(ST) includes the pixelelectrode 190 and a separate signal line (not shown), which is providedon the lower panel 100, overlaps the pixel electrode 190 via aninsulator. The separate signal line is supplied with a predeterminedvoltage such as the common voltage Vcom. Alternatively, the storagecapacitor C_(ST) includes the pixel electrode 190 and an adjacent gateline called a previous gate line, which overlaps the pixel electrode 190via an insulator.

For color display, each pixel uniquely represents one of three colorssuch as red, green, and blue colors or sequentially represents the threecolors in time, thereby obtaining a desired color. The three colors maybe primary colors, or other colors not specifically described herein.FIG. 2 shows an example in which each pixel includes a color filter 230representing one of the three colors in an area of the upper panel 200facing an associated pixel electrode 190. Alternatively, the colorfilter 230 may be provided on or under the pixel electrode 190 of thelower panel 100.

As shown in FIG. 2, a light blocking film 220, such as a black matrixfor preventing light loss, is formed on the upper panel 200 and hasopenings in areas corresponding to the pixel electrode 190 or the colorfilter 230.

A pair of polarizers (not shown) polarizing the light emitted from alight source unit (not shown) is attached on the outer surfaces of thepanels 100 and 200 of the panel assembly 300, respectively.Alternatively, one or more polarizers may be provided.

The gray voltage generator 800 generates a plurality of gray scalevoltages relating to the brightness of the LCD. The gray voltagegenerator 800 generates two sets of a plurality of gray voltages relatedto the transmittance of the pixels, and provides the gray voltages tothe data driver 500. The data driver 500 applies the gray voltages,which are selected for each data line D1-Dm, by control of the signalcontroller 600, to the data line respectively as a data signal. The grayvoltages in one set have a positive polarity with respect to the commonvoltage Vcom, while those in the other set have a negative polarity withrespect to the common voltage Vcom.

The gate driver 400 is connected to the gate lines G1-Gn of the LC panelassembly 300, synthesizes the gate-on voltage Von and the gate offvoltage Voff input from an external device to generate gate signalshaving combinations of the gate-on voltage Von and the gate-off voltageVoff for application to the gate lines G1-Gn. The gate driver 400 mayinclude a plurality of integrated circuits (“ICs”).

The data driver 500 is connected to the data lines D1-Dm of the LC panelassembly 300, applies data voltages selected from the gray voltagessupplied from the gray voltage generator 800 to the data lines D1-Dm,and may also include a plurality of ICs.

The gate driving circuits of the gate driver 400 or the data drivingcircuit of the data driver 500 may be implemented as an integratedcircuit (“IC”) chip mounted on the LC panel assembly 300, such as in a“chip on glass” (“COG”) type of mounting, or on a flexible printedcircuit (“FPC”) film of a tape carrier package (“TCP”) type, which areattached to the LC panel assembly 300. Alternately, the drivers 400 and500 may be integrated into the LC panel assembly 300 along with thedisplay signal lines G₁-G_(n) and D₁-D_(m) and the TFT switchingelements Q.

The temperature sensing unit 50 includes at least one temperature sensor51. The temperature sensor 51 generates a temperature sensing signal Vscorresponding to the temperature sensed by the temperature sensor 51 andoutputs the sensing signal Vs to the signal controller 600.

The signal controller 600 controls the gate driver 400 and the datadriver 500.

Referring to FIG. 3, the LC panel assembly 300 is divided into a displayregion DR on which the LC layer 3 is formed and a non-display region B.The non-display region B mainly corresponds to the border of the LCpanel assembly 300, adjacent an outermost periphery of the LC panelassembly 300, and is covered by the light blocking film 220, such as ablack matrix. The temperature sensors 51 of the temperature sensing unit50 are installed on the non-display region B. As shown in FIG. 3, thetemperature sensors 51 are installed two by two on an upper and a lowerpart of the LC panel assembly 300, respectively. In other words, twotemperature sensors 51 are installed on a first border portion of the LCpanel assembly 300, and two temperature sensors 51 are installed on asecond border portion of the LC panel assembly 300, where the firstborder portion is opposite the second border portion. However, thenumber of the temperature sensors 51 and the installed positions are notlimited to the illustrated embodiment. For example, the temperaturesensors 51 may be installed on a left and a right of the LC panelassembly 300 to sense a temperature of the LC panel assembly 300, andother alternative arrangements and quantities of temperature sensors 51would also be within the scope of these embodiments.

Now, the operation of the LCD will be described in detail.

The signal controller 600 is supplied with RGB image signals R, G, and Band input control signals controlling the display thereof such as avertical synchronization signal Vsync, a horizontal synchronizationsignal Hsync, a main clock signal MCLK, a data enable signal DE, etc.,from an external graphic controller (not shown). In response to theinput image signals R, G, and B and the input control signals, thesignal controller 600 processes the image signals R, G, and B suitablyfor the operation of the LC panel assembly 300 on the basis of the inputcontrol signals and a temperature sensing signals Vs, and generates gatecontrol signals CONT1 and data control signals CONT2. The signalcontroller 600 then provides the gate control signals CONT1 to the gatedriver 400, and the processed image signals R′, G′, and B′ and the datacontrol signals CONT2 to the data driver 500.

The gate control signals CONT1 include a vertical synchronizing startsignal, a scanning start signal STV, for informing the beginning of aframe and having instructions to start scanning, and at least one gateclock signal for controlling the output time of the gate-on voltage Von.The gate control signals CONT1 may further include an output enablesignal OE for defining the duration of the gate-on voltage Von.

The data control signals CONT2 include a horizontal synchronizationstart signal STH for informing the data driver 500 of the start of datatransmission for a group of pixels, a load signal LOAD havinginstructions to apply the data voltages to the data lines D1-Dm, and adata clock signal HCLK. The data control signal CONT2 may furtherinclude an inversion signal RVS for reversing the polarity of the datavoltages (with respect to the common voltage Vcom).

In response to the data control signals CONT2 from the signal controller600, the data driver 500 receives a packet of the image data DAT, theprocessed image signals, for the group of pixels from the signalcontroller 600, converts the image data DAT into analog data voltagesselected from the gray voltages supplied from the gray voltage generator800, and applies the data voltages to the data lines D1-Dm.

The gate driver 400 applies the gate-on voltage Von to the gate linesG1-Gn in response to the gate control signals CONT1 from the signalcontroller 600, thereby turning on the switching elements Q connectedthereto. The data voltages applied to the data lines D1-Dm are suppliedto the corresponding pixels through the activated switching elements Q.

The difference between the data voltage applied to the pixel and thecommon voltage Vcom is represented as a charged voltage across the LCcapacitor C_(LC), which is referred to as a pixel voltage. The LCmolecules in the LC capacitor C_(LC) have orientations depending on themagnitude of the pixel voltage, and the molecular orientations determinethe polarization of light passing through the LC layer 3. Thepolarizer(s) converts the light polarization into light transmittance.

By repeating this procedure by a unit of the horizontal period (which isdenoted by “1H” and equal to one period of the horizontal synchronizingsignal Hsync, the data enable signal DE, and the gate clock signal CPV),all gate lines G1-Gn are sequentially supplied with the gate-on voltageVon during a frame, thereby applying the data voltages to all pixels.When the next frame starts after finishing one frame, the inversioncontrol signal RVS, part of the data control signals CONT2, applied tothe data driver 500 is controlled such that the polarity of the datavoltages is reversed (which is referred to as “frame inversion”). Theinversion control signal RVS may also be controlled such that thepolarity of the data voltages flowing in a data line in one frame isreversed (for example, line inversion and dot inversion), or thepolarity of the data voltages in one packet is reversed (for example,column inversion and dot inversion).

Now, structures of an exemplary embodiment of a sensor and an exemplaryembodiment of an LCD having the sensor according to the presentinvention will be described with reference to FIGS. 4 to 5B.

FIG. 4 is a layout view of an exemplary embodiment of an LCD accordingto the present invention, FIG. 5A is a sectional view of the LCD shownin FIG. 4 taken along line VA-VA′, and FIG. 5B is a sectional view ofthe LCD shown in FIG. 4 taken along line VB-VB′.

A plurality of gate lines 121, a sensor control electrode 126, a sensorcontrol line 128, and a plurality of storage electrode lines 131 areformed on an insulating substrate 110 such as transparent glass or othersuitable transparent insulating material.

The gate lines 121 extend substantially in a transverse direction andare separated from each other and transmit gate signals. The gate lines121 may extend substantially parallel to each other. Each gate line 121includes a plurality of projections forming a plurality of gateelectrodes 124 and an end portion 129 having a large area for contactwith another layer or an external driving circuit. The gate lines 121may extend to be connected to a driving circuit that may be integratedon the insulating substrate 110.

The sensor control electrode 126 has a substantially rectangular shapehaving a horizontal side longer than a vertical side, where thehorizontal side of the sensor control electrode 126 may extend along thetransverse direction of the insulating substrate 110 and the verticalside of the control electrode 126 may extend along a longitudinaldirection across the insulating substrate 110. The sensor control line128 may extend in the longitudinal direction, with respect to the sensorcontrol electrode 126. While a specific arrangement of the sensorcontrol electrode 126 is illustrated, the sensor control electrode 126may be positioned in alternate peripheral areas of the insulatingsubstrate 110 as previously described with respect to FIG. 3. The sensorcontrol line 128 includes an end portion having a large area for contactwith another layer or an external driving circuit.

Each of the storage electrode lines 131 which are separated from thegate lines 121 also extends substantially in the transverse directionand is disposed between two adjacent gate lines 121. The storageelectrode lines 131 are supplied with a predetermined voltage such asthe common voltage of the other panel (not shown).

The gate lines 121, the sensor control electrode 126, the sensor controlline 128, and the storage electrode lines 131 are preferably made of analuminum Al-containing metal such as Al and an Al alloy, a silverAg-containing metal such as Ag and an Ag alloy, a copper Cu-containingmetal such as Cu and a Cu alloy, a molybdenum Mo-containing metal suchas Mo and a Mo alloy, chromium Cr, titanium Ti, or tantalum Ta. The gatelines 121, the sensor control electrode 126, the sensor control line128, and the storage electrode lines 131 may have a multi-layeredstructure including two films having different physical characteristics.If a two film structure is employed, one of the two films is preferablymade of a low resistivity metal including an Al-containing metal forreducing signal delay or voltage drop in the gate lines 121, the sensorcontrol electrode 126, the sensor control line 128, and the storageelectrode lines 131. The other film is preferably made of a materialsuch as Cr, Mo, a Mo alloy, Ta, or Ti, which has good physical,chemical, and electrical contact characteristics with other materialssuch as indium tin oxide (ITO) or indium zinc oxide (IZO). Some examplesof the combination of the two films that provide an appropriatecombination of preferable characteristics include a lower Cr film and anupper Al (Al—Nd alloy) film and a lower Al (Al alloy) film and an upperMo film.

In addition, the lateral sides of the gate line 121, the sensor controlelectrode 126, the sensor control line 128, and the storage line 131 aretapered, and the inclination angle of the lateral sides with respect toa surface of the substrate 110 is within a range of about 30 to about 80degrees.

A gate insulating layer 140, preferably made of silicon nitride (SiNx),is formed on the gate lines 121, the sensor control electrode 126, thesensor control line 128, and the storage electrode lines 131 and is alsoformed on the portions of the insulating substrate 110 not covered bythe gate lines 121, the sensor control electrode 126, the sensor controlline 128, and the storage electrode lines 131.

A plurality of semiconductor stripes 151, a plurality of semiconductorislands, and a semiconductor rectangle 155, preferably made ofhydrogenated amorphous silicon (abbreviated to “a-Si”), are formed onthe gate insulating layer 140. Each semiconductor stripe 151 extendssubstantially in a longitudinal direction, extending generallyperpendicularly to the storage electrode lines 131 and the gate lines121, and has a plurality of projections 154 branched out toward the gateelectrodes 124 and a plurality of protrusions disposed on the storageelectrode lines 131. The semiconductor rectangle 155 is separated fromthe semiconductor stripes 151 and has a shape substantially similar tothat of the sensor control electrode 126.

A plurality of ohmic contact stripes 161 and a plurality of ohmiccontact islands 165 are formed on the semiconductor stripes 151, and aplurality of ohmic contact islands 162 and 164 are formed on thesemiconductor rectangle 155. The ohmic contact stripes 161 and islands165, 162, and 164 are preferably made of silicide or n+hydrogenated a-Siheavily doped with an n-type impurity. Each ohmic contact stripe 161 hasa plurality of projections 163, and the projections 163 and the ohmiccontact islands 165 are located in pairs on the projections 154 of thesemiconductor stripes 151.

The ohmic contact islands 162 and 164 are located on the semiconductorrectangle 155, respectively, and are separated from each other.

The lateral sides of the semiconductor stripes 151, the semiconductorrectangle 155, and the ohmic contact stripes 161 and islands 165, 162,and 164 are tapered, and the inclination angles thereof with respect tothe insulating substrate 110 are preferably in a range between about 30to about 80 degrees.

A plurality of data lines 171, a plurality of drain electrodes 175, asensor input electrode 172, a sensor input line 176, a sensor outputelectrode 174, and a sensor output line 178 are formed on the ohmiccontact stripes 161 and islands 165 and the gate insulating layer 140.

The data lines 171 for transmitting data voltages extend substantiallyin the longitudinal direction and cross over the gate lines 121 and thestorage electrode lines 131. Each data line 171 has an end portion 179having a large area for contact with another layer or an externaldevice. A plurality of branches of each data line 171, which projecttoward the drain electrodes 175, form a plurality of source electrodes173.

The sensor input line 176 substantially extends in a longitudinaldirection, such as parallel to the sensor control line 128, and thesensor input electrode 172 includes a connection portion connected tothe sensor input line 176, a transverse portion extending in thetransverse direction substantially perpendicular to the longitudinaldirection and connected to the connection portion, and a plurality ofbranches extending from the connection portion via the transverseportion, the branches extending in the longitudinal direction like acomb.

The sensor output line 178 substantially extends in the longitudinaldirection, such as parallel to the sensor input line 176 and the sensorcontrol line 128, and the sensor output electrode 174 includes aconnection portion connected to the sensor output line 178, a transverseportion extending in the transverse direction substantiallyperpendicular to the longitudinal direction and connected to theconnection portion, and a plurality of branches extending from theconnection portion via the transverse portion, the branches extending inthe longitudinal direction like a comb.

The branches of the sensor input electrode 172 and the sensor outputelectrode 174 are alternately engaged through the semiconductorrectangle 155.

Each set of a gate electrode G 124, a source electrode S 173, and adrain electrode D 175 along with a projection 154 of a semiconductorstripe 151 form a TFT having a channel formed in the semiconductorprojection 154 disposed between the source electrode S 173 and the drainelectrode D 175.

The sensor control electrode 126, the sensor input electrode 172, andthe sensor output electrode 174 along with the semiconductor rectangle155 form a sensor transistor for a temperature sensor 51. Thespecifications of the sensor transistor are defined by a width W and alength L of the electrodes 126 and 172, and a thickness T of thesemiconductor rectangle 155.

The data lines 171, the source electrode 173, the drain electrode 175,the sensor input line 176, the sensor input electrode 172, the sensoroutput line 178, and the sensor output electrode 174 are preferably madeof a refractory metal including Cr, Mo, TV Ta, or alloys thereof. Theymay have a multi-layered structure, preferably including a lowresistivity film and a good contact film.

The semiconductor stripes 151 of the TFT array panel according to thisembodiment have almost the same planar shapes as the data lines 171 andthe drain electrodes 175 as well as the underlying ohmic contacts 161and 165. However, the projections 154 of the semiconductor stripes 151include some exposed portions, which are not covered with the data lines171 and the drain electrodes 175, such as portions located between thesource electrodes 173 and the drain electrodes 175.

Similar to the gate lines 121, the data lines 171, the source electrode173, the drain electrodes 175, the sensor input line 176, the sensorinput electrode 172, the sensor output line 178, and the sensor outputelectrode 174 have tapered lateral sides, and the inclination anglesthereof are in a range of about 30 to about 80 degrees with respect tothe insulating substrate 110.

A passivation layer 180 is formed on the data lines 171, the sourceelectrodes 173, the drain electrodes 175, the sensor input line 176, thesensor input electrode 172, the sensor output line 178, the sensoroutput electrode 174, and the exposed portions of the semiconductorstripes 151 and semiconductor rectangle 155, as well as any otherexposed portions of the gate insulating layer 140.

The passivation layer 180 is preferably made of a photosensitive organicmaterial having a good flatness characteristic, a low dielectricinsulating material such as a-Si:C:O and a-Si:O:F formed byplasma-enhanced chemical vapor deposition (“PECVD”), or an inorganicmaterial such as silicon nitride and silicon oxide. The passivationlayer 180 may have a double-layered structure including a lowerinorganic film and an upper organic film.

The passivation layer 180 has a plurality of contact holes 182, 185,186, and 187 exposing the end portions 179 of the data lines 171, thedrain electrodes 175, and end portions of the sensor input line 176 andthe sensor output line 178, respectively. The passivation layer 180 andthe gate insulating layer 140 also have a plurality of contact holes 181and 189 exposing the end portions 129 of the gate lines 121 and the endportion of the sensor control line 128, respectively.

A plurality of pixel electrodes 190 and a plurality of contactassistants 81, 82, 86, 87, and 89, which are preferably made of IZO orITO, are formed on the passivation layer 180. The contact assistants 81,82, 86, 87, and 89 are formed with respect to the contact holes formedin the passivation layer 180.

The pixel electrodes 190 are physically and electrically connected tothe drain electrodes 175 through the contact holes 185 such that thepixel electrodes 190 receive the data voltages from the drain electrodes175.

The pixel electrodes 190 supplied with the data voltages generateelectric fields in cooperation with the common electrode 270 on theupper panel 200, which reorient liquid crystal molecules in the liquidcrystal layer 3 disposed therebetween.

The pixel electrodes 190 may optionally overlap the gate lines 121 andthe data lines 171 to increase the aperture ratio.

The contact assistants 81, 82, 86, 87, and 89 are connected to theexposed end portions 129 of the gate lines 121, the exposed end portions179 of the data lines 171, the exposed end portion of the sensor inputline 176, the exposed end portion of the sensor output line 178, and theexposed end portion of the sensor control line 128 through the contactholes 181, 182, 186, 187, and 189, respectively. While not required, thecontact assistants 81, 82, 86, 87, and 89 are preferred to protect theexposed end portions and to complement the adhesiveness of the exposedportion and external devices.

The contact assistant 81 plays a part in connecting the end portions 129of the gate lines 121 and the gate driver 400 when the gate driver 400to supply gate signals is integrated on the insulating substrate 110,and may alternatively be omitted.

According to another embodiment of the present invention, the pixelelectrodes 190 are made of a transparent conductive polymer. For areflective LCD, the pixel electrodes 190 are made of an opaquereflective metal. In these cases, the contact assistants 81 and 82 maybe made of a material such as IZO or ITO different from the pixelelectrodes 190.

A size of the temperature sensor 51 integrated along with the gate lines121 and the data lines 171 upon the insulating substrate 110 and varyingan operating state or a resistance value thereof based on the sensedtemperature may be about 2 mm×2 mm or less. In addition, the sensorcontrol electrode 126 formed on the substrate 110 functions to blocklight from a light source (not shown) disposed below a lower part of theLC panel assembly 300. Such a feature does not limit light transmittanceof the LC panel assembly 300, however, since the positioning of thetemperature sensor 51 is generally limited to the non-display region B.

Exemplary embodiments of the temperature sensor 51 formed with the gatelines 121 and the data lines 171 on the non-display region B of the LCpanel assembly 300 include a diode type of temperature sensor and aresistor type of temperature sensor, as shown in FIGS. 6A to 7B, inaccordance with the connection of the sensor control line 128, thesensor input line 176, and the sensor output line 178, as furtherdescribed below.

FIG. 6A is an equivalent circuit diagram of an exemplary embodiment of adiode type of temperature sensor when a temperature sensor according toan exemplary embodiment of the present invention is the diode type oftemperature sensor, and FIG. 6B is a graph showing a characteristic ofan output voltage with respect to a temperature variation of the diodetype of temperature sensor shown in FIG. 6A. FIG. 7A is an equivalentcircuit diagram of an exemplary embodiment of a resistor type oftemperature sensor when a temperature sensor according to an exemplaryembodiment of the present invention is the resistor type of temperaturesensor, and FIG. 7B is a graph showing a characteristic of an outputvoltage with respect to a temperature variation of the resistor type oftemperature sensor shown in FIG. 7A.

An exemplary embodiment of when lines 128, 176, and 178 of thetemperature sensor 51 are connected as a diode type of temperaturesensor will be described with reference to FIGS. 6A and 6B.

Referring to FIG. 6A, a sensor control line G 128 of the temperaturesensor 51 is connected to a sensor output line D 178, and the sensorinput line S 176 of the temperature sensor 51 is connected to a groundGND such that a sensor transistor, that is, the temperature sensor 51,functions as a diode.

At this time, an output voltage V_(D) from the sensor output line D 178is represented as:V _(D) =V _(dd) −RI _(D)  [Equation 1]

Here, I_(D) is a current flowing through the sensor output line D 178, Ris a resistor connected to an exterior of the temperature sensor 51, andVdd is an input voltage.

At this time, for a voltage between the sensor control line G 128 andsensor input line S 176 and a voltage between the sensor output line D178 and the sensor input line S 176 by the connection between the sensorcontrol line G 128 and the sensor output line D 178, the I_(D) isexpressed as:

$\begin{matrix}{I_{D} = {\mu_{n}C_{g}\frac{W}{L}( {\frac{V_{D}^{2}}{2} - {V_{TH}V_{D}}} )}} & \lbrack {{Equation}\mspace{20mu} 2} \rbrack\end{matrix}$

Here, μ_(n) is electron mobility depending on a temperature variation,Cg is capacitance of the sensor input electrode 172, W is a channelwidth, L is a channel length, where W and L are measured such as shownin FIG. 4, and V_(TH) is a threshold voltage.

The electron mobility μ_(n) is represented as:

$\begin{matrix}{\mu_{n} = {\mu_{0}\;\frac{N_{C}{kT}}{n}e^{{- E_{a}}/{kT}}}} & \lbrack {{Equation}\mspace{20mu} 3} \rbrack\end{matrix}$

Here, μ₀ is extended state electron mobility, Nc is a state density atmobility edge, k is a Boltzmann constant, T is a temperature (K), n istotal electron density, and Ea is activation energy. In one embodiment,μ₀ is ˜6[cm²/vs], Nc is ˜2×10²¹[cm²/eV], k is 1.3805×10⁻²³[J/K], and Eais 0.13[eV].

As a result, with reference to [Equation 1] to [Equation 3], the outputvoltage V_(D) is varied based on a temperature variation.

The output voltage V_(D) of the temperature sensor 51 having theequivalent circuit shown in FIG. 6A is linearly varied as a temperatureis changed, as shown in FIG. 6B.

An exemplary embodiment of when lines 128, 176, and 178 of thetemperature sensor 51 are connected as a resistor type of temperaturesensor will be described with reference to FIGS. 7A and 7B.

As shown in FIG. 7A, a sensor control line G 128 is not supplied withany signals, a sensor input line S 176 is connected to a ground GNDthrough a resistor Rc, and a sensor output line D 178 is supplied withan externally applied driving voltage Vdd. In this embodiment, since thesensor control line G 128 is not supplied with any signals, atemperature sensor 51, that is, a sensor transistor, functions as aresistor Rs.

An output voltage Vout from the temperature sensor 51, that is, a sensortransistor, is represented as:

$\begin{matrix}{{Vout} = {\frac{Rc}{{Rs} + {Rc}}{Vdd}}} & \lbrack {{Equation}\mspace{20mu} 4} \rbrack\end{matrix}$

Rs is expressed as:

$\begin{matrix}{{Rs} = {\rho\;\frac{L}{WD}}} & \;\end{matrix}$and σ is expressed as:

$\sigma = {{{ne}\;\mu_{n}} = \frac{1}{\rho}}$

Here, e is carrier capacitance amount.

As described above, since the electron mobility μ_(n) is represented as[Equation 3], the output voltage Vout is varied based on a temperaturevariation.

The output voltage Vout with respect to a temperature variation isvaried as shown in FIG. 7B. As shown in FIG. 7B, though the outputvoltage Vout of the resistor type of temperature sensor is nonlinearlyvaried, the sensitivity of the temperature sensor 51 on the basis ofcharacteristics of a resistor is good.

In the resistor type of temperature sensor, since the sensor controlline G 128 is not supplied with any signal, a sensor control line G 176and a sensor control electrode 126 may be unnecessary.

Another exemplary embodiment of a resistor type of temperature sensoraccording to the present invention will be described with reference toFIGS. 8A and 8B. A structure of an LCD including the resistor type oftemperature sensor may be the same as that shown in FIGS. 4 and 5A andis therefore omitted.

FIG. 8A is a layout view of an exemplary embodiment of a resistor typeof temperature sensor according to the present invention and FIG. 8B isa sectional view of the resistor type of temperature sensor shown inFIG. 8A taken along the VIIIB-VIIIB′.

As shown in FIGS. 8A and 8B, a structure of another exemplary embodimentof a resistor type of temperature sensor according to the presentinvention is similar to that shown in FIGS. 4 and 5A except that asensor control electrode 126 and a sensor control line 128 are notformed.

That is, a gate insulating layer 140 is formed on an insulatingsubstrate 110 (with no sensor control electrode 126 and sensor controlline 128 present), and a semiconductor rectangle 155, having horizontalsides longer than vertical sides, is formed on the gate insulating layer140. A plurality of ohmic contacts 162 and 164 are formed on thesemiconductor rectangle 155. In addition, a sensor input line 176, asensor input electrode 172, a sensor output electrode 174, and a sensoroutput line 178 are formed on the ohmic contacts 162 and 164 and thegate insulating layer 140.

A passivation layer 180 is formed on the sensor input line 176, thesensor input electrode 172, the sensor output electrode 174, and thesensor output line 178, as well as on any exposed portions of the gateinsulating layer 140 and the semiconductor rectangle 155. Thepassivation layer 180 has a plurality of contact holes 186 and 187exposing end portions of the sensor input line 176 and the sensor outputline 178, respectively.

Contact assistants 86 and 87 may be formed on the passivation layer 180in combination with the contact holes 186, 187, respectively.

As described above, a resistor type of temperature sensor is designedwithout the sensor control line 128 and the sensor control electrode 126since they are not supplied with a signal.

For a diode type of temperature sensor and a resistor type oftemperature sensor according to embodiments of the present invention,exemplary graphs of output voltages actually outputted therefrom withrespect to a temperature variation are shown in FIGS. 9 and 10,respectively.

For exemplary purposes only, in FIGS. 9 and 10, a driving voltage Vdd isabout 5V, and W/L is 3200/4.5. In FIG. 9, a resistance value of theresistor R is about 620^(kΩ), and in FIG. 10 a resistance value of theresistor Rc is about 2^(kΩ).

As shown in FIGS. 9 and 10, the range of the sensed temperature of anLCD was about −20° C. to 80° C. In FIG. 9, temperatures were sensed by aunit of about 10° C., and in FIG. 10, temperatures were sensed by a unitof about 2.5° C. In FIG. 9, a voltage variation difference ΔV_(D) isabout 1.31V and in FIG. 10, a voltage variation difference ΔV_(out) isabout 4.37V. Thus, since dynamic sensibility of the output voltages fromthe temperature sensors is large, the output voltages are directly usedwithout separate signal processing such as filtering, amplifying, and soon.

The exemplary embodiments of temperature sensors according to thepresent invention sense an exact temperature corresponding to atemperature variation of an LC layer since the temperature sensors aredirectly integrated in the LC panel assembly along with the gate linesand the data lines.

According to the present invention, a temperature sensor is directlyintegrated in an LCD for sensing a temperature of the LCD, and therebythe temperature is exactly sensed without a large increment of amanufacturing cost. In addition, the controlling of a display device isachieved based on the exactly sensed temperature of the display device,and thereby an image quality of the display device is improved. Thedesign is improved and manufacturing cost is decreased since a separatetemperature sensor to be externally installed on the LCD is unnecessary.

Moreover, since driving characteristics of a temperature sensor arechanged by changing a connection of the lines thereof and a temperaturesensor having characteristics suitable for a display device andcircumference environment thereof is realized, the driving efficiency ofthe temperature sensor and the display device is improved.

Additionally, since the size of an area of the temperature sensorcontacting the surface of an LCD is increased due to the comb shape,while maintaining a small size of the temperature sensor, reliability ofsensing is improved and additional circuits are unnecessary.

While the present invention has been described in detail with referenceto the preferred embodiments, it is to be understood that the inventionis not limited to the disclosed embodiments, but, on the contrary, isintended to cover various modifications and equivalent arrangementsincluded within the spirit and scope of the appended claims. Moreover,the use of the terms first, second, etc. do not denote any order orimportance, but rather the terms first, second, etc. are used todistinguish one element from another. Furthermore, the use of the termsa, an, etc. do not denote a limitation of quantity, but rather denotethe presence of at least one of the referenced item.

1. A liquid crystal display panel comprising: a first panel; a secondpanel; a liquid crystal layer disposed between the first panel and thesecond panel; and, a temperature sensor formed on a first surface of thefirst panel, wherein the first surface of the first panel faces theliquid crystal layer, and the temperature sensor comprises a sensorinput electrode and a sensor output electrode; and wherein the sensorinput electrode comprises a first branch and the sensor output electrodecomprises a second branch, and he first branch faces the second branchin plan view.
 2. The liquid crystal display panel of claim 1, whereinthe first panel is a thin film transistor array panel.
 3. The liquidcrystal display panel of claim 1, wherein the temperature sensor isformed on a non-display region of the first panel.
 4. The liquid crystaldisplay panel of claim 1, further comprising a plurality of temperaturesensors formed on the first surface of the first panel.
 5. The liquidcrystal display panel of claim 1, wherein the first panel includes atleast one data line, and the sensor input electrode and the sensoroutput electrode are formed within a same layer of the first panel asthe data line.
 6. The liquid crystal display panel of claim 5, whereinthe first panel includes a substrate and at least one gate line formedon the substrate, and the temperature sensor includes a sensor controlelectrode formed within the same layer of the first panel as the gateline.
 7. The liquid crystal display panel of claim 1, wherein the firstbranch is engaged with the second branch through a semiconductor.